How to make a mesh look like glass
Use a glass shader.

The Glass BSDF is used to add a Glass-like shader mixing refraction and reflection at grazing angles. Like the transparent shader, only pure white will make it transparent
Color
Color of the surface, or physically speaking, the probability that light is ransmitted for each wavelength
Roughness
Influences sharpness of the refraction; perfectly sharp at 0.0 and smoother with higher values.
IOR
Index of refraction (IOR) defining how much the ray changes direction. At 1. 0 rays pass straight through like transparent; higher values give more refraction.
Normal
Normal used for shading.

https://docs.blender.org/manual/en/latest/render/shader_nodes/shader/glass.html?highlight=glass

For reflections, set something in the scene or the environment that will be reflected on the surface.
Read:
How to turn off reflections on glass